Method of treating gases.



l. HECHENBLEIKNER. METHOD OFTREATING GASES. APPLICATION man DEc.29.\s17.

Patenf-ed Apr. 1, 1919.

GENUIN HECHENIBLEIKNER, 0F CHARLOTTE, SOUTHERN ELECTRO-CHEMICAL COMPANY,

TIQN 0F NEW/JERSEY.

NORTH CAROLINA, lissie-Non To or NEW Yonx, N. Y., A CORPORA- METHOD OF TREATING GASES.

Specification of Letters Patent.

Patented Apr. 1, 1919.

Application med December 29, 1917. serial No. 209,577.

To all whom it may concern: o

Be it known that I, INGENUIN HECHEN BLEIKNER, a citizen of the United States, residing at Charlotte, in the county of Mecklenburg and State of North Carolina, have invented new and useful Improvements in Methods of Treating Gases, of which the following is a specification.

This invention relates to the treatment of ores or minerals containing potash or phosphorus, the method being particularly useful in the preparation of fertilizlng mate rial. In the -patent to Max M. Haft, dated IFebruary 20, 1912, No. 1,018,186, is set forth a process y potash, and in which process feldspar (orthoclase) as the source of potash and calcium sulfate as the source of phosphorus are heated in an electric furnace.

As contradistinguished from the process set forth in said patent I subject a mixture or charge of feldspar, calcium phosphateand the carbonaceous material, such as coke, to the action of an electric furnace so that the reaction is represented by the following equation:

wherein fn, is any figure.

After the oxidation of the phosphorus gases with airor oxygen the reaction 1s for the oxidation is preferably admitted at or near the lower or discharge end of the rotary kiln. The size and length of the rotary kiln which I use. in the practice of for obtaining phosphate ofmy method is dependent upon the character and amount of the mixture employed, and

the use of such kilnis exceedingly important in several respects in the successful conother important advantage of the use of such a rotary kiln 1n connection with my method is that it serves to purify the gases escaping from theffurnace. It is well known that in the treatment of a mixture of phosphate rock and silicious material, or silicious material containing potash, the materials used contain certain impurities which have a decided influence on the commercial operation of the process.' For instance, in such mixtures calcium iuorid is sometimes present in -quantities as highas 10%, and in the action of the electric furnace and under subsequent re-oxidation, gases or vapors are formed which contain not only phosphorus pentoxid, potassium oxid and carbon diox'id, but also certain impurities, such as silicon fluorid, silicon dioxid and the like, in addition to some mechanical dust. I have found hate rock andv that by passing these gases and vaporsl -themethod it is necessary that the gases while in thel rotary kiln be subor vapors a temperature sufficiently high to jected to prevent the condensation of the potassiumv phosphate or the phosphoric acid, yet low enough to. allow of the lbefore mentioned elimination of the impurities, such as the by the incoming tric furnace.

Fig. 4 is a transverse vertical sectionah View taken through the electric furnace and showing the even distribution of the charge SiO2 and SiF4. Thus the length and diameter of the kiln should be proportioned to the amount of charge for the furnace operation. 4It is also desirable to regulate ,the pressure of the gases in the kiln 1n such manner as t0v prevent the condensation of the phosphoric acid and potash vapors, as a relatively large pressure will result in the condensation ofY these latter. Therefore, after leaving the rotary kiln the gases are treated in a scrubbing system such for instance as is shown in my earlier Patent No.

1,112,211, or in an electric precipitator system for the recovery of the phosphoric acid and the potash, the proper pressure being maintained on the rotary kiln with the aid of an exhaustfan located beyond the latter, thusA enabling the gases to be drawn through the system by suction. ln the accompanying drawing I have shown one 'apparatus by means of which my method may be practised.

In the saidv drawings, l

Figure 1 is a view partly in vertical longitudinal section and partly in elevation ef an apparatus for practising any method.

F ig., 2 is a horizontal sectional view taken through the electric furnace on the line 2-2 I of Fig. 1 'and looking inthe direction of the arrow.

Fig. 3 is an enlarged vertical sectional vview of a portion of the apparatus where the rotary kiln discharges the charge to the electherein. l

Referring now to the accompanying drawings in detail, the letter A indicates the electric furnace provided with the usual carbon electrodes 1 and the tap hole 2 for the slag. This furnace is made practically air-tight, as is desired in an apparatus of this type for reasons now understood in the art, and adjacent its upper end is formed with an eX- tension 3 having a passage 4 through which the charge of material pases on its way to the furnace, anda gas exit passage 5 leading from the furnace to the rotary kiln JB, thesev two..passages 4 and 5 being separated by a partition wall 6.Y The rotary -kiln B is mounted on'a suitable supporting frame C, this kiln being supported at one endupon'a pipe section 7 connected with a dusticollector the opposite end cf the kiln being sup-y ported upon the collar or neck forming part of the wall of the gas exit passage 5.' As will be seen by reference to Fig. l, the rotary kiln is inclined upward from the electric furnace to the dust collector and is intended to be revolved by means of any suitable mechanism, such as is conventionally shown at E in said Fig. 1, the ends of the kiln nding bearings en the pipe section 7 and the neck 8, as just described. The pipe section 7 connecting the kiln with the dust collector D is provided with a suitable hopper 9 into which is dumped certain ingredients of the mixture to be fed into the electric furnace, such as the phosphate rock and the feldspar. Under the rotation of the kiln this material is fed slowly down the latter, traveling through a path of such a length as to be preheated by gases fowing up through the kiln. At the discharge end of the rotary kiln this material shown at F drops onto the floor 10 of the. feed passage 4, and is there mixed with ycoke or other carbcnaceous material indicated at G, such coke being fed down through the spout 11, and into the hopper 12 which discharges into the passage 4, as will be clearly understood by reference to Fig. 3. This hopper is provided with a hinged controllin gate 13 for the obvious purpose of'control ing the supply of coke allowed to enter the electric furnace. 1

` The now complete charge consisting of the in the feed passage a and fed into the furnace by means of the `reciprocating water-cooled plungers 14.- of the stoking mechanism, which 1S indicatedv as an entirety by the letter H. There are several advantages incident to this manner of feeding the complete charge into the furnace. In prior apparatus of this general type where the coke is fed into the kiln with the rock and sand mixture such cokein its passage through the kiln'becomes heated and partially Consumed so that its efficiency as a reducing impaired 'by the timeit entersthe furnace. Furthermore, with the usual ratus where the mixture was simply fed inte the furnace by gravity, it usually formed a pile or bank -at one side of the furnace instead of being evenly distributed over the entire combustion zone of the latter. This was due to thefact that no adequate means has been provided for spreading or leveling the charge in the electric furnace, and obviously it is impossible tcv do this by hand stoking owing to the enormously high temperature of the furnace as well as the closed gases or vapors hereinbefore mentioiied are generated and passing out throu h the exit passage 5 enter the rotary kiln ,passing up the saine f and preheating the mixture flowing down vthe latter. As before-indiagent is greatly type of appaiis .sorption by the incoming cated the rotary kiln diameter that the impurities in the gases or vapors such as the silica and silicon luorid are condensed Will be removed or eliminated from the outgoing gases by chemical abcharge and under the rotation of the kiln are carried back to the furnace and drawn off with the slag. Ofcourse the length of the kiln Will depend to a considerable degree upon the amount and vcharacter of the charge, in some instances a kiln of the length of feet being admirably adapted for an ordinary charge. Phosphorus and potash vapors and gases, however, require a lower temperature for condensation, and under the action of the suction fan J are drawn through the kiln and pipe section 7 to the dust collector D Where any fine mechanical dust Which may have been drawn through is trapped or caught, as the gases must pass down around the usual partition d in the dust collecting chamber.

After the yphosphorus and potash gases pass through the dust collector they are conducted to the usual scrubbing system or to an electric precipitator Where they are condensed and concentrated, as is Well understood in this art.

As the gases leave the electric furnace and just before they enter the rotary kiln they are subjected to oxidization through air or oxygen admitted through an air inlet K which preferably communicates with the upper portion of the passage 5, the air being drawn in at this point under the velocity `of the gases passing out of the electric furnace to the rotary kiln. j

While I have hei'ein shown and described one apparatus for carrying myV invention into effect, I Wish it to be understood that such method is not limited to practice with this particular apparatus, but other modification and variation may be made in such respect without departing from the spirit of the invention or exceeding the scope of the appended claims.

wWha-t I claim is: Y

1. The herein described method which comprises subjecting a mixture of phosphate rock, a silicious mineral containing potash and a carbonaceous substance to the heat of an electric furnace to volatilize the same, then oxidizing the resultant gases, and then removing or eliminating certain impurities is of such length and of an electric furnace potash constituents in gaseous and then removing or eliminating of the gases, such as Si()2 and Sill,A while maintaining the potash and phosphate substances in gaseous form.

2. The herein described method which comprises subjecting a mixture of calcium phosphate, feldspar and coke to the action to volatilize the same, then oxidizing the resultant gases after they leave the furnace and then removing or eliminating certain constituent gases such as Si()2 and Sil"4 While maintaining the form.

3. The herein described method Which comprises mixing phosphate rock anu feldspar and passing the same along a relatively long path to an electric furnace, the said mixture being preheated in its assage to the furnace, mixing coke with t e preheated mixture of phosphate rock and feldspar at the vpoint of entrance of the latter to the furnace, subjecting the charge to the heat of the furnace to volatilize the same, then oxidizing the resultant gases, certain impurities of lthe gases While maintaining the potash and phosphate substances 1n gaseous form.

4. 'The herein described method which comprises heating a mixture of phosphate rock, a silicious mineral and a carbonaceous substance in an electric furnace to volatilize the same, then oxidizing theresultant gases,

then passing the gases through. aV rotary kiln and in contact with an incoming charge of the mixture to remove certain constituents from the gases and which constituents are returned to the furnace With the incoming charge.

5. The herein described method which whereof I have -hereunto set my hand.

INGENUIN HECHENBLEIKNER. 

